PURPOSE: To perform curve inspection and interior probing with one single carrier to simplify operation and reduce a cost by moving a self-running carrier in a duct with an inspecting unit and a probing unit selectively mounted.

CONSTITUTION: A target to which laser light is to be applied and a television camera are provided as an inspecting unit 2, and a center adjusting member for aligning the target with the center of a duct is provided on a side, while a television camera 34 and a driving means for rotating it are provided as a probing unit 3. Further a seat for mounting the unit 2 and the unit 3 is formed on a carrier 1, as well as connectors 8, 9, 19, 30 for electrically connecting them are provided. At the time of curve inspection, laser light is placed along the duct and also the carrier 1 with the unit 2 mounted is moved in the duct to perform the curve inspection, while at the time of interior probing, probing of the duct is performed by moving the carrier 1 with the unit 3 mounted. Therefore preparation of both tasks of the inspection and interior probing is simplified and a working cost can be reduced.